The present invention relates to a spiral parts heat treatment apparatus and method, and a spiral part, and more particularly, to a technique suitable for a machining and assembling apparatus for a coil spring as a spiral part that requires a heat treatment process.
According to the machining and assembling apparatus for a spring as a spiral part, after a wire such as a music wire or stainless steel wire is coiled, its outer dimension (free length) is inspected, and is heat-treated at about 300.degree. C. to 500.degree. C. for a predetermined period of time in order to remove the residual stress of coiling. For this purpose, a large number of coil springs that have been subjected to coiling are placed together in a case, are placed in the heat treatment furnace of a heat treatment apparatus in units of cases, and are heat-treated.
To automatically assemble coil springs completed in this manner, the coil springs are aligned with an aligning unit, e.g., a parts feeder, and are separated apart from each other one by one. The separated coil spring is held with a robot or the like, is moved, and is built into a container main body or the like.
With this method, since the springs are entangled with each other in the parts feeder, the reliability of alignment before the parts are held with the robot or the like is low, to cause a decrease in operability of the automatic assembly line. As a countermeasure for this, among conventional heat treatment apparatuses, one having an outer appearance shown in the perspective view of FIG. 11 is known.
Referring to FIG. 11, coil springs W manufactured by a spring manufacturing machine 1160 are discriminated by an inspection unit 1150 and are sequentially dropped into a gutter-shaped accepting member 1171. The coil springs W are moved downward along the accepting member 1171 and are spirally passed through a heat treatment furnace 1170, thereby heat-treating the coil springs W.
Alternatively, as in the perspective view of the outer appearance of a conventional heat treatment apparatus shown in FIG. 12, coil springs W manufactured by a spring manufacturing machine 1160 are discriminated by an inspection unit 1150 and are sequentially dropped into a gutter-shaped accepting member 1171. The coil springs W are fitted, with a transfer robot 1181, on pins P that are to hold the springs on a moving belt conveyor. The pins P are passed through a heat treatment furnace 1180 by the belt conveyor, thereby heat-treating the coil springs W.
As disclosed in Japanese Patent Laid-Open No. 5-007961, there is also proposed a "post-treatment apparatus for a coiled product". According to this apparatus, the hook integrally formed with a coil spring is hung from a rod. The hook is positioned with respect to a spiral member which rotates about this rod and which is formed with a spiral groove. The coil springs are fed to a heat treatment unit one by one.